Electric furnace.



M. SHOE LD. ELECTRIC FURNACE. APPLICATION HLED MAR. 6. 1918- Patented Au". 6, 1918.

MARK SHOELD, OF CHICAGO, ILLINOIS, ASSIGNOR TO ARMOUR FERTILIZER WORKS, OF

GEICAGO, ILLINOIS, CORPORATION OF NEW JERSEY.

ELECTRIC FURNACE.

Application filed March 6, 1918.- Serial mi. 220,677. I

To aZZ whom it may concern Be it known that I, MARK Snonnn, a subject of the King of Sweden, residing at Chicago, in the county of Cook and Stateof Illinois,

have invented certain new and useful Im-' provements in Electric Furnaces, of which the following is a specification.

The present invention pertains to improvements in electric aiid similar furnaces adapt ed to be operated under great heat, such, for example, as those used for the production of aluminum nitrid, which are run at a temperature in the neighborhood of 2000 centigrade.

The primeobject or purpose of the inven tion is the provision of a furnace of this type which shall be capable of successfully withstanding such high temperatures for an indefinite period and which shall so bring the solid material to be acted upon or chemically changed by reason of the heat into such adequate, intimate, and uniform association with the gas employed that all of such mate rial will be chemically converted into the desired product, rather than only a portion thereof because of insufficient or uneven distribution and intermixing of the material and gas' In other words, the furnace is so designed and constructed that a desirable, thorough, and even dispersion of the gas through the material is certain to take place at the point of greatest heat. The resistance of the furnace to the destructive action of the intense heat is effected by the nature of the lining employed, the disposition and arrangement of the parts, and the use of a gas which at the high temperature employed will not detrimentally act on the lining.

A further object of the preferred embodiment of the invention is to provide the heat for the furnace by means of an electric are between terminals or electrodes in the heating chamber and to conduct or convey the ,material to be. acted upon through such chamber in the most efficient manner without conflict with such electrodes or arc. Preferably, the furnace is designed to convey or transport the material through it antomatically by gravity by reason of an inrectly beneath the are, which, of course, is the region of the greatest heat, whereby the gas traveling through the material in 'the opposite direction tends to become evenly and uniformly distributed therethrough in such vertical portion of the chute or passage, and; consequently, there is a complete, uniform, and full chemical reaction throughout the entire body of material at this point. If such chute, channel, or passage were straight and inclined without such upright or offset portion the gas would have atendency to pass thron h the upper portion only of the material, tins not coming into proper and full contact with the lower or underlying strata.

To permit those skilled in this art to have a full and complete understanding of this invention and its various advantages, and the means whereby the foregoing objects may be attained by an appliance of simple structure, I have illustrated a preferred embodlmc'nt of the same in the accompanying sirable form of the improved furnace in a vertical section.

I Turning to such drawing, it will be apparout that the heating compartment or cham ber 10 which may be of any suitable shape and size is lined or walled with carbon 11, (graphite may be used as a lining but carbon is preferred) formed or shaped to provide a heat chamber or cavity of the desired conformation and to supply the inclined, offset chute or passage hereinafter described. The furnace, as a whole, is heat insulated at 12 by, any approved means, which, of course, require no description, as this invention is not dependent upon the particular material employed for such purpose either as to substance pr form.

The carbon lining referred to and the outer or inclosing heatinsulating material are recessed at the top of the furnace for the Patented Aug. e, 1918.

accommodation of an upper, vertically-arranged graphite electrode or terminal 13 which is insulated from the carbon lining, as shown, by reason of its aperture 14 being larger in cross-section than the COI'ltSpOIltling dimensions of theelectrode. The coinpanion lower graphite electrode 15 is also insulated from the carbon lining as indicated in the drawing.

An inclined chute 16 extends through the furnace, the heating chamber 10 forming a central enlargement thereof. This passage comprises an upper inclined section 17 leading downwardly to the electrode chamber 10, gradually and uniformly delivering the solid material to be treated (such as briquets coniposed of comminnted alumina and carbon with suitable binder) by gravity to the lower portion of the heating chamber beneath the elect ric-arc between the electrodes, such are being practically in the middle of the chamher, as shown. Directly beneath the arc. and centrally accommo lating the lower electrode H, as well as the 'gradually-descending body of material traveling down the chute and disposed around. such electrode, the chute has a. somewhat short, vertical section or portion 18 which in turn connect-s or commi'inicates with a lower or delivery inclined pai-t it). By this means the moving body of material, although fed into the furnace by sliding down an inclined plane, travels verticallyat the hottest point in the furnace or rather descends vertically while it is heated.

to its highest temperature, and is then delivered out of the furnace through a downwardly-sloping extension.

(las, such as nitrogen, either pure or slightly impure, by reason of the presence of a small percentage of carbon-inonoxid, is

v adu itt ed to the lower part of chute 15) at 20,

2t), and is caused to travel up such passage, being discharged at 21 near the top, thus traversing the chute in a direction the opposite of the direction of movement of the solid material. If the whole length of the chute were inclined, that is to say, if it did not have the vertical otl'set specified, such gas would have a tendency to traverse the material with which the, chute is filled only throiwh its u )er ortion thus resultin in a its uneven distribution throughout the crossl section of the material, with an obvious iiietlicient and incomplete reaction, because some. of the parts of the material would be subjected either to no gas or to an insulticient, quantity to produce the chemical reaction required. liy making the portion of the chute adjacent to the arc vertical, the gas has no tendency to pass more easil through any particular portion of the body ()fJIlztfO-Ilill than any other portion and hence at: this part of the furnace such gas is substantially evenly and uniformly disspect.

persed or distributed through the material and the desired chemical effect. occurs under the action of the high heat, the degree or amount of which can be easily regulated by adjusting the position of the are up or down as occasion may require.

It is to be understood, of course, that the top and bottom ends of the chute are maintained closed in any approved manner not shown, whereby the gas will necessarily tra'v erse the path indicated, the solid mate rial being more or less continuously admit ted and discharged.

The positioning of the electrodes v'ertically is not necessarily required, as they may be otherwise located, and, so far as the broader filtlll'tb of the invention are concerned, it is not essential that the heat chamher be heated from the interior. Since, however, the electrodes are somewhat fragile and subject to unnecessary strains when not located one above the other in alinement, the deviceillustrated is preferable in this re- As has been explained the apparatus set forth designed to continuously carry out the process and there is a desirable and economical tendency therein to concentrate the heat i i the center ofthe furnace. The cool incoming body of material is initially or preliminarily heated more or less by the upwardly traveling heated gas, such material is also subjccted sidewise to the heat of the are as it enters the heat chamber and before it descends the vertical central portion of the chute, and the hot body of solid material as it, descends the lower sloping or inclined part of the chute transmits its heat to the incoming gas, traveling through it in the opposite direction, thus desirably raising the temperature of the gas and reducing the temperature of the material soon to be discharged from the furnace.

The important features of this invention to be borne particularly in mind are, first that the feed of material is continuous and automatic; second, that the gas is caused to act uniformly on such material at the point of highest temperature where the chemical reaction occurs; third, that a carbon lining is employed and such gas is used as will not. cause the lining to dcterio'ate 01' be consinned under the high temperatures canployedj fourtlnthat the appliance is simple in structuri,etfective in action, not readily damaged or injured, and is capable of sus* tained high heat without detrimental ett'ccts; and. fifth, that the structure is such that the electric arc is contained in the heat chamber, the body of material being caused to pass through such compartment. without coming into contact with the arc and without injuring the electrodes.

As has been indicated, this furnace is not restricted to any particular use and it may be modified in structure in man minor features without departure from t e substance and essence of the invention and without sacrificing any of its substantial benefits and advantages. It is not essential that the chute ofiset be vertical or that the furnace have a single passage only, one of the features being the change of direction of travel ofthe solid material, or the gas, or both to secure their complete and unlform intermingling.

I claim:

1. In an electric-furnace of the character described, the combination of a heat-chamber, a carbon-linin for said chamber, and electrodes in said 0 amber exclusive 'of said lining adapted to maintain between them an electric-arc to heat said chamber, substantially as described.

2. In an electric-furnace of the. character described, the combination of a heat chamber, a carbon-lining for said chamber, and

means exclusive of said linin and outside of the body of the material eing treated to electrically heat said chamber, substantially as described.

3. In .an electric-furnace of the character described, the combination of a heat chamher, a carbondining for said chamber, and means exclusive of saidlining to produce an electric-arc in said chamber outside of the body of material being treated, substantially as described. V

4:. In an electric-furnace of the character described, the combination of a heat chain: her, a carbon-lining for said chamber, means exclusive of said lining to produce an elcctrie-arc in said chamber outside of the body of the material beingtreated, and means to substantially continuously feed the material to be acted upon by the heat through said chamber. substantially as described.

5. In an electric-furnace of the character described, the combination of a heat-chamher, an electrically-condiictive lining for said chamber, and electrodes in said chamber exclusive of said lining adapted to main lain an electric-arc between them to heat said chamber, substantially as described.

6. In an electric-furnace of the character described. the combination of a heat chamber, a carbon lining for said chamber, means chamber, and means to pass a gas through so said chamber, substantially as described.

8. In an electric-furnace of the character described, the combination of a heat chainber, means to electrically heat said'chamber, and means to feed the material to he treated through said chamber and change its direction of travelwhile it' is substantially at its hottest temperature, substantially as described.

9. In an electric-furnace of the character 76 described, the combination of a heat chamber, means to produce an electric-arc in said chamber, and means to feed the material to be treated through said chamber and change its direction 'of travel adjacent to the posi- 80 tion of said arc, substantially-as described.

. 10. In an electric-furnace of the character described, the combination of a heat cham' ber, means to electrically heat said chamber, and means to pass a gas through said chamher andchange its direction of travel while it is substantially at its hottest temperature, substantially as described.

11. In anelectric-furnace of the character described, the combination of -a heat chem-- ber, means to produce an electric-arc in said chamber, and means to pass a gas through said chamber and change its direction of travel adjacent to the position of said arc, substantially as described.

12. In an electric-furnace of the character described, the combination'of a heat chamber, means to electrically heat said chamber, means to feed the solid material to be treated through said chamber and change its dire'ction of travel while it is substantially at its hottest temperature, and means to pass gas through said material in a direction opposite of that of its travel. substantially as described. y

13. In an electric-furnace of the character; described, the combination of a heat chamber, means to produce an electric-arc in said chamber, means to feed the material to be treated through said chamber and change its direction of travel adjacent to said are, and means to pass a gas through said material in a direction substantially the oppo' site of that of its direction of travel, substantially as described.

14. In an electric-furnace of the character described, the combination of a heat-cha nber, means to produce an electric-arc in said chamber, means to feed the material to be treated through said chamber beneath said are and change its direction of travel substantially beneath such arc,-substantially as described.

15. In an electric'furnace of the character described, the combination of a heat chamber, means to produce an electric-arc in said chamber, means to feed the solid material to be treated through said chamber be neath said arc and change its direction of travel substantially beneath said are. and means to pass gas through said material in a direction substantially the opposite of that of its travel, substantially as described.

16. In an electric-furnace of the character described, the combination of a heat cham her, and means to electrically heat said chamber, said furnace having an inclined passage therethrough for conveying the material to be treated, said passage being ofi'set at practically the point of hottest temperature of the material, substantially as described.

17. In an electric-furnace of the character described, the combination of a heat chamber, and means to electrically heat said chamber, said furnace having an inclined passage therethrough for conveying the material to be treated, said passage being olfset substantially vertically at practically the point of hottest temperature of the material, substantially as described.

18. In an electric-furnace of the character described, the combination of a heat chamber, and means to electrically heat said chamber, said furnace having an inclined passage therethrough for conveying gas, said passage being ofi'set at the point of hottest temperature of the gas, substantially as described.

1!). In an electric-furnace of the characte described, the combination of a heat chamber, and means to electrically heat said chamber, said furnace having an inclined passage therethrough for conveying gas, said passage being ofi'set substantially vertically at the point of hottest temperature of the gas, substantially as described.

20. In an electric-furnace of the charac 3 teldescribed, the combination of a heat chamber, and means to electrically heat said chamber, said furnace hav ng an inclined passage therethrough for conveying downi \vardly the materia to be treated an "o veying upwardly the gas, said passage being ofi'set at. the point of hottest temperature of the material, substantially as described. t

21. In an electric-furnace of the character described, the combination of a heat chamber, and means to electrically heat said chamber, said furnace having an inclined passage therethrough for conveying downwardly the material to be treated and conveying upwardly the gas, said passage being ofi'set substantially vertically at the. point of hottest temperature of the? material, substantially as described.

22. In an electric-furnace of the character described, the combination of a heat chamber, and means to produce an. electric-arc in said chamber, said furnace having an inclined passage therethrough for conveying the material to be treated and for the gas to be used, said passage being otl'set at a point substantially beneath such arc, substantially as described.

23 In an electric-furnace of the character described, the combination of a heat chamher, and means to produce an electric-are in said chamber, said furnace having an inclined passage therethrough for conveying the material to be treated and for the gas to be used, said passage being otl'set substantially vertically at a point substantially beneath such are, substantially as described.

24. In an eleetric-turmice of the character described, the combination of a heal chamber, and verticallyarranged electrodes adapted to sustain an electric are between them in said chamber, said furnace having an inclined passage therethrough for conveying the niateriallto be treated and for directing the passage of gas, said passage being oi'l'set practically vertically substantially at a point beneath the a'rc between said electrodes, substantially as described.

MARK SHOELI). 

